full beard
A full beard consists of hair on the chin, the cheeks, and the sideburns, without any natural or shaven gap.
In real life a full beard also includes a mustache, but that's not true for a lot of bearded anime characters.
If the character has a mustache, you can tag it as:
A full beard can also be a thick beard, or thin beard stubble.
Visual comparison Danbooru post #6608064
This tag implicates beard (learn more).